1、Designation: A340 14Standard Terminology ofSymbols and Definitions Relating to Magnetic Testing1This standard is issued under the fixed designation A340; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONIn preparing this glossary of terms, an attempt has been made to avoid, where possible, vectoranalysis and differential equations so as
3、 to make the definitions more intelligible to the average workerin the field of magnetic testing. In some cases, rigorous treatment has been sacrificed to securesimplicity, but it is believed that none of the definitions will prove to be misleading.It is the intent of this glossary to be consistent
4、in the use of symbols and units with those found inANSI/IEEE 260-1978 and USA Standard Y 10.5-1968.Part 1Symbols Used in Magnetic TestingSymbol Term cross-sectional area of B coilA cross-sectional area of specimenA solid areaBHmagnetic inductionmagnetic flux densityB excursion range of inductionBb b
5、iased inductionBdremanent inductionBdmremanenceBdHdenergy product(BdHd)mmaximum energy productBincremental inductionBiintrinsic inductionBmmaximum induction in a hysteresis loopBmaxmaximum induction in a flux current loopBrresidual inductionBrsretentivityBssaturation inductioncf crest factorCM cycli
6、cally magnetized conditiond lamination thicknessDBdemagnetizing coefficientdf distortion factorDmmagnetic dissipation factorE exciting voltageE1induced primary voltageE2induced secondary voltageEfflux voltsf cyclic frequency in hertz magnetomotive forceff form factorH magnetic field strengthH excurs
7、ion range of magnetic field strengthHbbiasing magnetic field strengthHccoercive field strengthHciintrinsic coercive field strengthHcscoercivityHddemagnetizing field strengthHincremental magnetic field strengthHgair gap magnetic field strengthHLac magnetic field strength (from an assumedpeak value of
8、 magnetizing currentHmmaximum magnetic field strength in a hyster-esis loopHmaxmaximum magnetic field strength in a flux-current loopHpac magnetic field strength (from a measuredpeak value of exciting current)Htinstantaneous magnetic field strength (coinci-dent with Bmax)Hzac magnetic field strength
9、 force (from an as-sumed peak value of exciting current)I ac exciting current (rms value)Icac core loss current (rms value)Idcconstant currentImac magnetizing current (rms value)J magnetic polarizationk coupling coefficient! flux path length!1effective flux path length!ggap length+ (also N ) flux li
10、nkage1This terminology is under the jurisdiction of ASTM Committee A06 onMagnetic Properties and is the direct responsibility of Subcommittee A06.92 onTerminology and Definitions.Current edition approved Oct. 1, 2014. Published October 2014. Originallyapproved in 1949. Last previous edition approved
11、 in 2011 as A34003a (2011).DOI: 10.1520/A0340-14.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1+mmutual flux linkageL self inductanceL1core inductanceLincremental inductanceLiintrinsic inductanceLmmutual inductanceL0initial inductan
12、ceLsseries inductanceLwwinding inductancem magnetic momentM magnetizationm total mass of a specimenm1active mass of a specimenNDdemagnetizing factorN1turns in a primary windingN2turns in a secondary windingN1I/!1ac excitationp magnetic pole strength3 permeanceP active (real) powerPaapparent powerPa
13、(B;f)specific apparent powerPctotal core lossPc (B;f)specific core lossPcincremental core lossPenormal eddy current core lossPeincremental eddy current core lossPhnormal hysteresis core lossPhincremental hysteresis core lossPqreactive (quadrature) powerPrresidual core lossPwwinding loss (copper loss
14、)Pzexciting powerPz (B;f)specific exciting powerQmmagnetic storage factor5 reluctanceR1core resistanceRwwinding resistanceS lamination factor (stacking factor)SCM symmetrically cyclically magnetized conditionTcCurie temperaturew lamination widthWhhysteresis loop losslinear expansion, coefficient (av
15、erage) incremental tolerance hysteretic angle loss anglecos magnetic power factorpproton gyromagnetic ratiommagnetic constant density susceptibilityac Permeabilities:aideal permeabilityLinductance permeabilityL incremental inductance permeability0dinitial dynamic permeabilityppeak permeabilitypincre
16、mental peak permeabilityiinstantaneous permeabilityzimpedance permeabilityzincremental impedance permeabilitydc Permeabilities: normal permeabilityabsabsolute permeabilityddifferential permeabilityincremental permeabilityeffeffective circuit permeabilityiintrinsic permeabilityiincremental intrinsic
17、permeabilitymmaximum permeability0initial permeabilityrrelative permeabilityv(also m) space permeabilityrevreversible permeability/cot figure of merit reluctivity the numeric 3.1416 resistivity magnetic fluxN flux linkage (see +) mass susceptibility0initial susceptibility angular frequency in radian
18、s per secondPart 2Definition of Terms Used in Magnetic Testingac excitation, N1I/1the ratio of the rms ampere-turns ofexciting current in the primary winding of an inductor to theeffective flux path length of the inductor.active (real) power, Pthe product of the rms current, I,inanelectrical circuit
19、, the rms voltage, E, across the circuit, andthe cosine of the angular phase difference, between thecurrent and the voltage.P 5 EI cosDISCUSSIONThe portion of the active power that is expended in amagnetic core is the total core loss, Pc.aging coefficientthe percentage change in a specific mag-netic
20、 property resulting from a specific aging treatment.DISCUSSIONThe aging treatments usually specified are:(a) 100 h at 150C or(b) 600 h at 100C.aging, magneticthe change in the magnetic properties of amaterial resulting from metallurgic change due to a normalor specified aging condition.DISCUSSIONThi
21、s term implies a deterioration of the magneticproperties of magnetic materials for electronic and electricalapplications, unless otherwise specified.air-gap magnetic field strength, Hgthe magnetic fieldstrength required to produce the induction existing at somepoint in a nonmagnetic gap in a magneti
22、c circuit.DISCUSSIONIn the cgs-emu system of units, Hgis numerically equalto the induction existing at such a point and exceeds the magnetic fieldstrength in the magnetic material.amorphous alloya semiprocessed alloy produced by a rapidquenching, direct casting process resulting in metals withnoncry
23、stalline structure.ampere (turn), Athe unit of magnetomotive force in the SIsystem of units. The symbol A represents the unit of electriccurrent, ampere, in the SI system of units.ampere per metre, A/mthe unit of magnetic field strength inthe SI system of units.anisotropic materiala material in whic
24、h the magnetic prop-erties differ in various directions.anisotropy of lossthe ratio of the specific core loss measuredwith flux parallel to the rolling direction to the specific coreloss with flux perpendicular to the rolling direction.A340 142anisotropy of loss 5Pc B;f! lPc B;f! twhere:Pc (B;f) l=
25、specific core loss value with flux parallel to therolling direction, W/lb W/kg, andPc (B;f) t= specific core loss value with flux perpendicular tothe rolling direction, W/lb W/kg.DISCUSSIONThis definition of anisotropy normally applies to elec-trical steels with measurements made in an Epstein frame
26、 at a fluxdensity of 15 kG 1.5 T and a frequency of 60 Hz (see Test MethodA343).anisotropy of permeabilitythe ratio of relative peak perme-ability measured with flux parallel to the rolling direction tothe relative peak permeability measured with flux perpen-dicular to the rolling direction.anisotro
27、py of permeability 5prlprtwhere:prl= relative peak permeability value with flux parallel tothe rolling direction, andprt= relative peak permeability value with flux perpendicu-lar to the rolling direction.DISCUSSIONThis definition of anisotropy normally applies to elec-trical steels with measurement
28、s made in an Epstein frame at a fluxdensity of 15 kG 1.5 T and a frequency of 60 Hz (see Test MethodA343).antiferromagnetic materiala feebly magnetic material inwhich almost equal magnetic moments are lined up antipar-allel to each other. Its susceptibility increases as the tem-perature is raised un
29、til a critical (Nel) temperature isreached; above this temperature the material becomes para-magnetic.apparent power, Pathe product (volt-amperes) of the rmsexciting current and the applied rms terminal voltage in anelectric circuit containing inductive impedance. The compo-nents of this impedance a
30、s a result of the winding will belinear, while the components as a result of the magnetic corewill be nonlinear. The unit of apparent power is the volt-ampere, VA.apparent power, specific, Pa(B;f)the value of the apparentpower divided by the active mass of the specimen, that is,volt-amperes per unit
31、 mass. The values of voltage andcurrent are those developed at a maximum value of cycli-cally varying induction B and specified frequency f.area, Athe geometric cross-sectional area of a magnetic pathwhich is perpendicular to the direction of the induction.Bloch walla domain wall in which the magnet
32、ic moment atany point is substantially parallel to the wall surface. Seealso domain wall.Bohr magnetona constant that is equal to the magneticmoment of an electron because of its spin. The value of theconstant is (9 274 078 1021erg/gauss or9 274 078 1024J/T).cgs-emu system of unitsthe system for mea
33、suring physicalquantities in which the base units are the centimetre, gram,and second, and the numerical value of the magneticconstant, m, is unity.coercive field strength, Hcthe (dc) magnetic field strengthrequired to restore the magnetic induction to zero after thematerial has been symmetrically c
34、yclically magnetized.coercive field strength, intrinsic, Hcithe (dc) magnetic fieldstrength required to restore the instrinsic magnetic inductionto zero after the material has been symmetrically cyclicallymagnetized.coercivity, Hcsthe maximum value of coercive field strengththat can be attained when
35、 the magnetic material is symmetri-cally cyclically magnetized to saturation induction, BS.core, laminateda magnetic component constructed bystacking suitably thin pieces of magnetic material which arestamped, sheared, or milled from sheet or strip material.Individual pieces usually have an insulati
36、ng surface coatingto minimize eddy current losses in the assembled core.core, matedtwo or more magnetic core segments assembledwith the magnetic flux path perpendicular to the matingsurface.core, powder (dust)a magnetic core comprised of smallparticles of electrically insulated metallic ferromagneti
37、cmaterial. These cores are characterized by low hysteresis andeddy current losses.core, tape-wounda magnetic component constructed by thespiral winding of strip material onto a suitable mandrel. Thestrip material usually has an insulating surface coating whichreduces interlaminar eddy current losses
38、 in the finished core.core loss, ac eddy current, incremental, Pethe power losscaused by eddy currents in a magnetic material that iscyclically magnetized.core loss, ac eddy current, normal, Pethe power losses asa result of eddy currents in a magnetic material that issymetrically cyclically magnetiz
39、ed.DISCUSSIONThe voltage is generally assumed to be across theparallel combination of core inductance, L1, and core resistance, R1.core loss, ac, incremental, Pcthe core loss in a magneticmaterial when the material is subjected simultaneously to adc biasing magnetizing force and an alternating magne
40、tizingforce.core loss, residual, Prthe portion of the core loss power, Pc,which is not attributed to hysteresis or eddy current lossesfrom classical assumptions.core loss, ac, specific, Pc(B;f)the active power (watts) ex-pended per unit mass of magnetic material in which there isa cyclically varying
41、 induction of a specified maximum value,B, at a specified frequency, f.core loss, ac, (total), Pcthe active power (watts) expended ina magnetic circuit in which there is a cyclically alternatinginduction.A340 143DISCUSSIONMeasurements of core loss are normally made withsinusoidally alternating induc
42、tion, or the results are corrected fordeviations from the sinusoidal condition.core loss densitythe active power (watts) expended in amagnetic core in which there is a cyclically varying induc-tion of a specified maximum value, B, at a specifiedfrequency, f, divided by the effective volume of the co
43、re.DISCUSSIONThis parameter is normally used only for non-laminatedcores such as ferrite and powdered cores.core platea generic term for any insulating material, formedmetallurigically or applied externally as a thin surfacecoating, on sheet or strip stock used in the construction oflaminated and ta
44、pe wound cores.coupling coefficient, kthe ratio of the mutual inductancebetween two windings and the geometric mean of theindividual self-inductances of the windings.crest factor, cfthe ratio of the maximum value of a periodi-cally alternating quantity to its rms value.DISCUSSIONFor a sinusoidal var
45、iation the crest factor is =2.Curie temperature, Tcthe temperature above which a fer-romagnetic material becomes paramagnetic.current, ac core loss, Icthe rms value of the in-phasecomponent (with respect to the induced voltage) of theexciting current supplied to a coil which is linked with aferromag
46、netic core.current, ac exciting, Ithe rms value of the total currentsupplied to a coil that is linked with a ferromagnetic core.DISCUSSIONExciting current is measured under the condition thatany other coil linking the same core carries no current.current, ac, magnetizing, Imthe rms value of the magn
47、etiz-ing component (lagging with respect to applied voltage) ofthe exciting current supplied to a coil that is linked with aferromagnetic core.current, dc, Idca steady-state dc current. A dc currentflowing in an inductor winding will produce a unidirectionalmagnetic field in the magnetic material.cu
48、stomary unitsa set of industry-unique units from thecgs-emu system of units and U.S. inch-pound systems andunits derived from the two systems.DISCUSSIONExamples of customary units used in ASTM A06standards include:Quantity NameQuantitySymbol Unit Name Unit SymbolMagnetic field strength H oersted OeM
49、agnetic induction (magneticflux density)B gauss GSpecific core loss Pc(; f) watt/pound W/lbcyclically magnetized condition, CMa magnetic material isin a cyclically magnetized condition when, after having beensubjected to a sufficient number of identical cycles ofmagnetizing field, it follows identical hysteresis or flux-current loops on successive cycles which are not symmetri-cal with respect to the origin of the axes.demagnetizati
